This Phase II SBIR effort will research and test a novel system for blood analysis that utilizes micro-electro- mechanical systems (MEMS) fabricated chips and radio-frequency electric impedance (EI) interrogation signals to differentiate blood cell types. The project's long-term objective is to create an inexpensive handheld hematology analyzer with single-use disposable cartridges capable of performing a complete blood count (CBC) using a 12 muL sample of whole blood. In pursuit of this long term objective, this Phase II SBIR focuses on successfully miniaturizing the necessary conductance and impedance-based cell counting technologies, design and testing of the single-use CBC microfluidic cartridges, as well as testing the supporting electronics and micro-fluidics interfaces for the proposed handheld system. The system will be powered by a programmable personal device assistant (PDA) for test control, data collection, analysis of raw EI cell data, and results display. Specifically, three aims will be pursued: (1) design and testing of a CBC disposable cartridge; (2) design and testing of the PDA driven electronics and analysis software; and (3) integration and performance testing of the CBC analyzer system components. If successful, the eventual introduction of such a groundbreaking point-of-care device would constitute a technological breakthrough in hematology and will offer health care providers a valuable alternative to the traditional hematology analyzers currently used in most clinical laboratories. Anticipated benefits from such a device include dramatically lower test costs, rapid test results, next-to-patient care & portability, and increased efficiency in diagnosis and treatment. This new point-of-care system has the potential to significantly reduce the CBC equipment and per-test cost and could result in millions of dollars saved in the US healthcare industry alone (2004 US CBC market estimated at $12 billion), with even greater worldwide cost savings potential. This new micro-fabricated platform technology and its first product application (i.e., a handheld CBC analyzer with disposable cartridges) is the only known commercial effort of its kind. The successful completion of an inexpensive, portable handheld hematology analyzer would constitute a significant breakthrough in hematology by offering healthcare providers a less expensive, simpler platform to conduct the most common blood diagnostic test currently performed in the US. Such a breakthrough will dramatically improve testing efficiencies with its single-use, disposable test cartridges and will make it possible to rapidly test patients at bedside, in remote locations, or in areas with limited healthcare resources. Finally, this new point-of-care system could significantly reduce current CBC equipment and per-test costs, thereby resulting in millions of dollars saved in the US healthcare and insurance industries (2004 US CBC market estimated at $12 billion), with even greater worldwide healthcare impacts in developing countries. [unreadable] [unreadable] [unreadable]